MainActivity: rework layout to avoid lag

ScrollView + RecyclerView lead to very slow loading times for the
recycler, like a few seconds on the biggest Medusae pages. Turns out it
binds every ViewHolder instantly, losing all the recycling behavior!
Following some guidelines on StackOverflow fixed this, because official
docs could not.
This commit is contained in:
dece 2021-12-10 23:50:18 +01:00
parent 57854e56dc
commit 3cba46ad5d
8 changed files with 144 additions and 38 deletions

View file

@ -25,6 +25,7 @@ android {
release { release {
minifyEnabled false minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro' proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
signingConfig signingConfigs.debug
} }
} }
compileOptions { compileOptions {
@ -42,6 +43,7 @@ dependencies {
implementation 'com.google.android.material:material:1.4.0' implementation 'com.google.android.material:material:1.4.0'
implementation 'androidx.constraintlayout:constraintlayout:2.1.2' implementation 'androidx.constraintlayout:constraintlayout:2.1.2'
implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:2.4.0" implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:2.4.0"
implementation 'androidx.legacy:legacy-support-v4:1.0.0'
testImplementation 'junit:junit:4.13.2' testImplementation 'junit:junit:4.13.2'
androidTestImplementation 'androidx.test.ext:junit:1.1.3' androidTestImplementation 'androidx.test.ext:junit:1.1.3'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0' androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'

View file

@ -1,5 +1,6 @@
package dev.lowrespalmtree.comet package dev.lowrespalmtree.comet
import android.annotation.SuppressLint
import android.text.SpannableString import android.text.SpannableString
import android.text.style.UnderlineSpan import android.text.style.UnderlineSpan
import android.util.Log import android.util.Log
@ -12,6 +13,8 @@ import dev.lowrespalmtree.comet.databinding.*
class ContentAdapter(private var content: List<Line>, private val listener: ContentAdapterListen) : class ContentAdapter(private var content: List<Line>, private val listener: ContentAdapterListen) :
RecyclerView.Adapter<ContentAdapter.ContentViewHolder>() { RecyclerView.Adapter<ContentAdapter.ContentViewHolder>() {
private var lastLineCount = 0
interface ContentAdapterListen { interface ContentAdapterListen {
fun onLinkClick(url: String) fun onLinkClick(url: String)
} }
@ -35,7 +38,6 @@ class ContentAdapter(private var content: List<Line>, private val listener: Cont
} }
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ContentViewHolder { override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ContentViewHolder {
Log.d(TAG, "onCreateViewHolder: type $viewType")
return LayoutInflater.from(parent.context).let { return LayoutInflater.from(parent.context).let {
when (viewType) { when (viewType) {
TYPE_EMPTY -> ContentViewHolder.Empty(GemtextEmptyBinding.inflate(it)) TYPE_EMPTY -> ContentViewHolder.Empty(GemtextEmptyBinding.inflate(it))
@ -54,7 +56,6 @@ class ContentAdapter(private var content: List<Line>, private val listener: Cont
} }
override fun onBindViewHolder(holder: ContentViewHolder, position: Int) { override fun onBindViewHolder(holder: ContentViewHolder, position: Int) {
Log.d(TAG, "onBindViewHolder: position $position")
val line = content[position] val line = content[position]
when (holder) { when (holder) {
is ContentViewHolder.Paragraph -> holder.binding.textView.text = is ContentViewHolder.Paragraph -> holder.binding.textView.text =
@ -75,9 +76,28 @@ class ContentAdapter(private var content: List<Line>, private val listener: Cont
override fun getItemCount(): Int = content.size override fun getItemCount(): Int = content.size
fun setContent(content: List<Line>) { /**
this.content = content * Replace the content rendered by the recycler.
*
* The new content list may or may not be the same object as the previous one, we don't
* assume anything. The assumptions this function do however are:
* - If the new content is empty, we are about to load new content, so clear the recycler.
* - If it's longer than before, we received new streamed content, so *append* data.
* - If it's shorter or the same size than before, we do not notify anything and let the caller
* manage the changes itself.
*/
@SuppressLint("NotifyDataSetChanged")
fun setContent(newContent: List<Line>) {
content = newContent.toList() // Shallow copy to avoid concurrent update issues.
if (content.isEmpty()) {
Log.d(TAG, "setContent: empty content")
notifyDataSetChanged() notifyDataSetChanged()
} else if (content.size > lastLineCount) {
val numAdded = content.size - lastLineCount
Log.d(TAG, "setContent: added $numAdded items")
notifyItemRangeInserted(lastLineCount, numAdded)
}
lastLineCount = content.size
} }
sealed class ContentViewHolder(view: View) : RecyclerView.ViewHolder(view) { sealed class ContentViewHolder(view: View) : RecyclerView.ViewHolder(view) {

View file

@ -41,6 +41,7 @@ fun parseData(
channel.send(line) channel.send(line)
} }
} }
channel.close()
} }
return channel return channel
} }

View file

@ -2,6 +2,7 @@ package dev.lowrespalmtree.comet
import android.annotation.SuppressLint import android.annotation.SuppressLint
import android.app.Activity import android.app.Activity
import android.content.ActivityNotFoundException
import android.content.Intent import android.content.Intent
import android.content.Intent.ACTION_VIEW import android.content.Intent.ACTION_VIEW
import android.net.Uri import android.net.Uri
@ -18,6 +19,7 @@ import androidx.lifecycle.viewModelScope
import androidx.recyclerview.widget.LinearLayoutManager import androidx.recyclerview.widget.LinearLayoutManager
import dev.lowrespalmtree.comet.databinding.ActivityMainBinding import dev.lowrespalmtree.comet.databinding.ActivityMainBinding
import kotlinx.coroutines.Dispatchers import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.Job
import kotlinx.coroutines.launch import kotlinx.coroutines.launch
import java.net.UnknownHostException import java.net.UnknownHostException
import java.nio.charset.Charset import java.nio.charset.Charset
@ -27,6 +29,8 @@ class MainActivity : AppCompatActivity(), ContentAdapter.ContentAdapterListen {
private lateinit var pageViewModel: PageViewModel private lateinit var pageViewModel: PageViewModel
private lateinit var adapter: ContentAdapter private lateinit var adapter: ContentAdapter
private val currentUrl get() = binding.addressBar.text
@SuppressLint("SetTextI18n") @SuppressLint("SetTextI18n")
override fun onCreate(savedInstanceState: Bundle?) { override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState) super.onCreate(savedInstanceState)
@ -50,8 +54,11 @@ class MainActivity : AppCompatActivity(), ContentAdapter.ContentAdapterListen {
} }
} }
pageViewModel.linesLiveData.observe(this, { adapter.setContent(it) }) binding.contentSwipeLayout.setOnRefreshListener { openUrl(currentUrl.toString()) }
pageViewModel.alertLiveData.observe(this, { alert(it) })
pageViewModel.state.observe(this, { updateState(it) })
pageViewModel.lines.observe(this, { updateLines(it) })
pageViewModel.alert.observe(this, { alert(it) })
} }
override fun onLinkClick(url: String) { override fun onLinkClick(url: String) {
@ -63,29 +70,68 @@ class MainActivity : AppCompatActivity(), ContentAdapter.ContentAdapterListen {
var uri = Uri.parse(url) var uri = Uri.parse(url)
if (!uri.isAbsolute) { if (!uri.isAbsolute) {
uri = if (!base.isNullOrEmpty()) joinUrls(base, url) else toGeminiUri(uri) uri = if (!base.isNullOrEmpty()) joinUrls(base, url) else toGeminiUri(uri)
Log.d(TAG, "openUrl: '$url' - '$base' - '$uri'")
Log.d(TAG, "openUrl: ${uri.authority} - ${uri.path} - ${uri.query}")
binding.addressBar.setText(uri.toString())
} }
when (uri.scheme) { when (uri.scheme) {
"gemini" -> pageViewModel.sendGeminiRequest(uri) "gemini" -> {
else -> startActivity(Intent(ACTION_VIEW, uri)) binding.addressBar.setText(uri.toString())
pageViewModel.sendGeminiRequest(uri)
}
else -> openUnknownScheme(uri)
} }
} }
private fun alert(message: String) { private fun updateState(state: PageViewModel.State) {
AlertDialog.Builder(this) Log.d(TAG, "updateState: $state")
.setTitle(R.string.alert_title) when (state) {
PageViewModel.State.IDLE -> {
binding.contentProgressBar.hide()
binding.contentSwipeLayout.isRefreshing = false
}
PageViewModel.State.CONNECTING -> {
binding.contentProgressBar.show()
}
PageViewModel.State.RECEIVING -> {
binding.contentSwipeLayout.isRefreshing = false
}
}
}
private fun updateLines(lines: List<Line>) {
Log.d(TAG, "updateLines: ${lines.size} lines")
adapter.setContent(lines)
}
private fun alert(message: String, title: String? = null) {
val builder = AlertDialog.Builder(this)
if (title != null)
builder.setTitle(title)
else
builder.setTitle(title ?: R.string.alert_title)
builder
.setMessage(message) .setMessage(message)
.create() .create()
.show() .show()
} }
private fun openUnknownScheme(uri: Uri) {
try {
startActivity(Intent(ACTION_VIEW, uri))
} catch (e: ActivityNotFoundException) {
alert("Can't open this URL.")
}
}
class PageViewModel : ViewModel() { class PageViewModel : ViewModel() {
private var lines = ArrayList<Line>() private var requestJob: Job? = null
val linesLiveData: MutableLiveData<List<Line>> by lazy { MutableLiveData<List<Line>>() } val state: MutableLiveData<State> by lazy { MutableLiveData<State>(State.IDLE) }
val alertLiveData: MutableLiveData<String> by lazy { MutableLiveData<String>() } private var linesList = ArrayList<Line>()
val lines: MutableLiveData<List<Line>> by lazy { MutableLiveData<List<Line>>() }
val alert: MutableLiveData<String> by lazy { MutableLiveData<String>() }
enum class State {
IDLE, CONNECTING, RECEIVING
}
/** /**
* Perform a request against this URI. * Perform a request against this URI.
@ -93,43 +139,58 @@ class MainActivity : AppCompatActivity(), ContentAdapter.ContentAdapterListen {
* The URI must be valid, absolute and with a gemini scheme. * The URI must be valid, absolute and with a gemini scheme.
*/ */
fun sendGeminiRequest(uri: Uri) { fun sendGeminiRequest(uri: Uri) {
Log.d(TAG, "sendRequest: $uri") Log.d(TAG, "sendRequest: URI \"$uri\"")
viewModelScope.launch(Dispatchers.IO) { state.postValue(State.CONNECTING)
requestJob?.apply { if (isActive) cancel() }
requestJob = viewModelScope.launch(Dispatchers.IO) {
val response = try { val response = try {
val request = Request(uri) val request = Request(uri)
val socket = request.connect() val socket = request.connect()
val channel = request.proceed(socket, this) val channel = request.proceed(socket, this)
Response.from(channel, viewModelScope) Response.from(channel, viewModelScope)
} catch (e: UnknownHostException) { } catch (e: UnknownHostException) {
alertLiveData.postValue("Unknown host \"${uri.authority}\".") signalError("Unknown host \"${uri.authority}\".")
return@launch return@launch
} catch (e: Exception) { } catch (e: Exception) {
Log.e(TAG, "sendGeminiRequest coroutine: ${e.stackTraceToString()}") Log.e(TAG, "sendGeminiRequest coroutine: ${e.stackTraceToString()}")
alertLiveData.postValue("Oops! Whatever we tried to do failed!") signalError("Oops! Whatever we tried to do failed!")
return@launch return@launch
} }
if (response == null) { if (response == null) {
alertLiveData.postValue("Can't parse server response.") signalError("Can't parse server response.")
return@launch return@launch
} }
Log.i(TAG, "sendRequest: got ${response.code} with meta \"${response.meta}\"") Log.i(TAG, "sendRequest: got ${response.code} with meta \"${response.meta}\"")
when (response.code) { when (response.code) {
Response.Code.SUCCESS -> handleRequestSuccess(response) Response.Code.SUCCESS -> handleRequestSuccess(response)
else -> alertLiveData.postValue("Can't handle code ${response.code}.") else -> signalError("Can't handle code ${response.code}.")
}
} }
} }
private fun signalError(message: String) {
alert.postValue(message)
state.postValue(State.IDLE)
} }
private suspend fun handleRequestSuccess(response: Response) { private suspend fun handleRequestSuccess(response: Response) {
lines.clear() state.postValue(State.RECEIVING)
linesList.clear()
lines.postValue(linesList)
val charset = Charset.defaultCharset() val charset = Charset.defaultCharset()
var lastUpdate = System.currentTimeMillis()
for (line in parseData(response.data, charset, viewModelScope)) { for (line in parseData(response.data, charset, viewModelScope)) {
lines.add(line) linesList.add(line)
linesLiveData.postValue(lines) val time = System.currentTimeMillis()
if (time - lastUpdate >= 100) { // Throttle to 100ms the recycler view updates…
lines.postValue(linesList)
lastUpdate = time
} }
} }
lines.postValue(linesList)
state.postValue(State.IDLE)
}
} }
companion object { companion object {

View file

@ -50,6 +50,7 @@ class Request(private val uri: Uri) {
} }
} }
Log.d(TAG, "proceed coroutine: reading completed") Log.d(TAG, "proceed coroutine: reading completed")
channel.close()
} }
return channel return channel
} }

View file

@ -70,6 +70,7 @@ class Response(val code: Code, val meta: String, val data: Channel<ByteArray>) {
} }
// Forward all incoming data to the Response channel. // Forward all incoming data to the Response channel.
channel.consumeEach { responseChannel.send(it) } channel.consumeEach { responseChannel.send(it) }
responseChannel.close()
} }
// Return the response here; this stops consuming the channel from this for-loop so // Return the response here; this stops consuming the channel from this for-loop so
// that the coroutine above can take care of it. // that the coroutine above can take care of it.

View file

@ -24,28 +24,48 @@
android:layout_width="match_parent" android:layout_width="match_parent"
android:layout_height="match_parent" android:layout_height="match_parent"
android:layout_margin="4dp" android:layout_margin="4dp"
android:ems="10"
android:hint="@string/url" android:hint="@string/url"
android:imeOptions="actionDone|actionGo" android:imeOptions="actionDone|actionGo"
android:importantForAutofill="no" android:importantForAutofill="no"
android:inputType="textUri" android:inputType="textUri"
android:text="" /> android:text=""
tools:ignore="TextContrastCheck" />
</com.google.android.material.appbar.CollapsingToolbarLayout> </com.google.android.material.appbar.CollapsingToolbarLayout>
</com.google.android.material.appbar.AppBarLayout> </com.google.android.material.appbar.AppBarLayout>
<androidx.core.widget.NestedScrollView <androidx.swiperefreshlayout.widget.SwipeRefreshLayout
android:id="@+id/scroll_view" android:id="@+id/content_swipe_layout"
android:layout_width="match_parent" android:layout_width="match_parent"
android:layout_height="wrap_content" android:layout_height="wrap_content"
app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior"> app:layout_behavior="@string/appbar_scrolling_view_behavior">
<RelativeLayout
android:id="@+id/content_inner_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior">
<androidx.recyclerview.widget.RecyclerView <androidx.recyclerview.widget.RecyclerView
android:id="@+id/content_recycler" android:id="@+id/content_recycler"
android:layout_width="match_parent" android:layout_width="match_parent"
android:layout_height="match_parent" android:layout_height="wrap_content"
android:orientation="vertical" /> android:orientation="vertical"
</androidx.core.widget.NestedScrollView> app:layout_constraintTop_toTopOf="parent" />
<androidx.core.widget.ContentLoadingProgressBar
android:id="@+id/content_progress_bar"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="match_parent"
android:layout_height="16dp"
android:layout_alignParentTop="true"
android:layout_marginTop="-8dp"
android:indeterminate="true"
android:visibility="gone" />
</RelativeLayout>
</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>
</androidx.coordinatorlayout.widget.CoordinatorLayout> </androidx.coordinatorlayout.widget.CoordinatorLayout>

View file

@ -2,5 +2,5 @@
<Space xmlns:android="http://schemas.android.com/apk/res/android" <Space xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_width="match_parent"
android:layout_height="8dp" android:layout_height="8dp"
android:background="@color/black"> android:background="@color/black"
</Space> android:orientation="vertical"></Space>